Oracle CDB管理实现多租户管理功能_数据库_开发者

CDB的管理

1.当前容器

通过SYS_CONTEXT命令来查看，

col con_id format a10

col con_name format a20

select sys_context('userenv','con_id') as con_id,sys_context('userenv','con_name') as

con_name from dual;

通过show 命令

[oracle@oracle-db-19c ~]$ sqlplus / as sysdba
SQL*Plus: Release 19.0.0.0.0 - Production on Wed Nov 30 11:07:06 2022
Version 19.3.0.0.0
Copyright (c) 1982, 2019, Oracle.  All rights reserved.
Connected to:
Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.3.0.0.0
SQL> col con_id format a10
SQL> col con_name format a20
SQL> select sys_context('userenv','con_id') as con_id,sys_context('userenv','con_name') as con_name from dual;
CON_ID     CON_NAMEpython
---------- --------------------
1          CDB$ROOT
SQL> 
SQL> show con_name;
CON_NAME
------------------------------
CDB$ROOT
SQL> 
SQL> show pdbs;
    CON_ID CON_NAME                       OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------
         2 PDB$SEED                       READ ONLY  NO
         3 PDB1                           READ WRITE NO
         4 PDB2                           MOUNTED
         5 CNDBAPDB                       MOUNTED
         6 CNDBAPDB3                      MOUNTED
         7 CNDBAPDB2                      MOUNTED
         8 CNDBAPDB4_FRESH                READ ONLY  NO
SQL> alter session set container=PDB1;
Session altered.
SQL> show user;
USER is "SYS"
SQL> show con_name;
CON_NAME
------------------------------
PDB1
SQL>

2.修改CDB的参数

[oracle@oracle-db-19c ~]$ 
[oracle@oracle-db-19c ~]$ sqlplus / as sysdba
SQL*Plus: Release 19.0.0.0.0 - Production on Wed Nov 30 11:26:54 2022
Version 19.3.0.0.0
Copyright (c) 1982, 2019, Oracle.  All rights reserved.
Connected to:
Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.3.0.0.0
SQL> col name for a20
SQL> select con_id,name,ispdb_modifiable from v$system_parameter where name='open_cursors';
    CON_ID NAME                 ISPDB
---------- -------------------- -----
         0 open_cursors         TRUE
SQL> set linesize 200
SQL> shphpow parameter open_cursors;
NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
open_cursors                         integer     300
SQL> alter system set open_cursors = 301;
System altere编程客栈d.
SQL> show parameter open_cursors;
NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
open_cursors                         integer     301
SQL> alter session set container=PDB1;
Session altered.
SQL> show parameter open_cursors;
NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
open_cursors                         integer     301
SQL>

3.修改PDB的参数

1.使用ALTER DATABASE 命令修改CDB的参数

以公共用户身份连接到CDB root,可以通过ALTER PLUGGABLE DATABASE 语句来修改PDB的相关配置
也可以直接连接到PDB中，通过ALTER DATABASE 语句来修改相关配置。

(1) 修改CDB。当公共用户连接的是CDB root时，通过ALTER DATABASE 命令执行如下语句会修改整个CDB.

startup/recovery/logfile/controlfile/standbydatabase/instance/security/RENAME/GLOBAL_NAME/ENABLE LOCK CHANGE TRACKING/DISABLE LOCK CHANGE TRACKING

(2) 只修改CDB root 。当公共用户连接的是CDB root时，通过ALTER DATABASE 命令执行如下语句只修改CDB root

datafile/DEFAULT EDITION/DEFAULT TABLESPACE/ DEFAULT TEMPORARY TABLESPACE

(3) 修改一个或多个PDB。公共用户连接到CDB root时，可以通过ALTER PLUGGABLE DATABASE 语句修改PDB的打开状态（MOUNT/READ ONLY/READ WRITE）,以及保存/忽略PDB的打开状态。

2.使用ALTER DATABASE命令修改CDB的UNDO模式

[oracle@oracle-db-19c ~]$ sqlplus / as sysdba
SQL*Plus: Release 19.0.0.0.0 - Production on Wed Nov 30 13:39:46 2022
Version 19.3.0.0.0
Copyright (c) 1982, 2019, Oracle.  All rights reserved.
Connected to:
Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.3.0.0.0
SQL> show user;
USER is "SYS"
SQL> show con_name;
CON_NAME
------------------------------
CDB$ROOT
SQL> col property_name for a30;
SQL> col property_value for a20;
SQL> select property_name,property_value from database_properties where property_name='LOCAL_UNDO_ENABLED';
PROPERTY_NAME                  PROPERTY_VALUE
------------------------------ --------------------
LOCAL_UNDO_ENABLED             TRUE
SQL>

TRUE代表本地UNDO模式，FLASE代表共享UNDO模式。

（2）共享UNDO模式转换为本地UNDO模式的步骤如下：

关闭CDB，代码如下

shutdown immediate;

以UPGRADE方式启动CDB，代码如下：

STARTUP UPGRADE;

确认当前容器是CDB root,代码如下：

show con_name;

启动本开发者_mariadb地UNDO，代码

ALTER DATABASE LOCAL UNDO ON;

重启 CDB，正常打开，

SHUTDOWN IMMEDIATE;STARTUP;

(3) 本地UNDO模式转换为共享UNDO模式的步骤如下：

关闭CDB

shutdown immediate

以UPGRADE方式启动CDB，

STARTUP UPGRADE;

确认当前容器是CDB root，

SHOW CON_NAME

禁用本地UNDO

ALTER DATABASE LOCAL UNDO OFF

重启CDB,正常打开，

SHUTDOWN IMMEDIATE;STARTUP;

4.CDB和PDB参数保存位置说明

# CDB
SQL> 
SQL> show con_name;
CON_NAME
------------------------------
CDB$ROOT
SQL> show parameter spfile;
NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
spfile                               string      /u01/app/oracle/product/19.3.0
                  php                               /dbhome_1/dbs/spfilecdb1.ora
SQL>
SQL> alter session set container=PDB1;
Session altered.
SQL> show parameter spfile;
NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
spfile                               string      /u01/app/oracle/product/19.3.0
                                                 /dbhome_1/dbs/spfilecdb1.ora
SQL> alter session set container=cdb$root;
Session altered.
SQL>

CDB Fleet特性

Fleet就是一个逻辑的CDB集合。其中，Lead CDB 是CDB Fleet中用于监控和管理其它CDB的。

在CDB Fleet中，可以通过以下方式来访问CDB和PDB中的数据：

CDB视图
GV$视图
CONTAINERS子句
容器映射

配置CDB FLEET环境

1.设置Lead CDB ,通过以下命令启动该特性：

# 启动 LEAD CDB
SQL> 
SQL> alter database set lead_cdb = true;
Database altered.
SQL> select property_value from database_properties where property_name='LEAD_CDB';
PROPERTY_VALUE
--------------------
TRUE
SQL>